Advanced Torque Control Scheme for the High Speed Switched Reluctance Motor

Abstract

High speed drive systems are much interested in the industrial application such as blower, compressor, pump and spindle due to the compact size and high efficiency. In recent, the demands of high speed drives are much increased due to the mechanical advantages of high speed system. SRMs (Switched Reluctance Motors) have simple structure and inherent mechanical strength without rotor winding and permanent magnet. These mechanical structures are suitable for harsh environments such as high temperature and high speed applications. Although SRMs have many advantages for the high speed applications, high torque ripple is still main problem to be applied to a high speed drives. SRM(Switched Reluctance Motor) has been researched in last 150 years. However, significant amount of attention to this motor type was given in last few decades thank to the development of microcontrollers, power semiconductors and CAD technology. But compared with other motor, SRM cannot be operated without inverter. Therefore, it is suitable for variable speed application because inverter is essential. SRM is a doubly salient machine because both the stator and rotor have salient poles. Flux is created by concentrated stator winding only. There are no permanent magnets, commutators, and windings in rotor side. So, SRM has simple and robust rotor structure that is very important in high speed application because centrifugal force is very high when rotor rotates at high speed. Due to a simple structure at the stator and the rotor, SRM can compete with other types of motor. And because SRM has only the windings at the stator, SRM achieves high efficiency especially in high speed region. With these advantageous features, SRM deserves to be investigated and it is good candidate for high speed drive systems in particular.